Biology and life table of Brevicoryne brassicae and Lipaphis pseudobrassicae (Hemiptera: Aphididae) on Brassica oleracea var. acephala

Abstract

The aphid Brevicoryne brassicae is a key pest of brassicas (cabbage). However, Lipaphis pseudobrassicae is increasingly common in brassica areas, and as it is better adapted to high temperatures, it can become the main pest in warmer seasons or in regions with higher temperatures. Biological research has aided in the management of aphids in different crops, reducing the use of insecticides. However, to accomplish this and ensure agricultural sustainability, we need to understand the biological parameters of insect pests associated with crops. Therefore, this study aimed to evaluate the biological parameters and population development of L. pseudobrassicae and B. brassicae in the laboratory. Nymphs at 24 h of age were maintained on cabbage (Brassica oleracea L. var. acephala) seedlings (25±2 °C, RH: 60% and 12 h photophase) and monitored at 24 h intervals until death. The immature phase was similar between B. brassicae (6.46 days) and L. pseudobrassicae (6.57 days) with high mortality of 1st and 2nd instar B. brassicae nymphs. Adults of B. brassicae lived longer in the pre- and post-reproductive periods, but a shorter time in the reproductive period. Time interval of each generation (T), innate ability to increase in number (rm), and finite rate of increase (λ) were similar between species. The specific fertility of B. brassicae was superior to that of L. pseudobrassicae. However, the net reproduction rate (Ro) of L. pseudobrassicae (17.62) was higher than that of B. brassicae (9.98). The time required for the population to double the number of individuals (TD) was shorter for L. pseudobrassicae (3.62 days) when compared to B. brassicae (4.37 days). These results indicate that L. pseudobrassicae may become a more relevant aphid for brassicas in Brazil, compared to B. brassicae.